


Mounted

by thewinchesterlifestyle



Category: Supernatural
Genre: Alpha/Beta/Omega Dynamics, Animal Instincts, Barebacking, Big Breed Dogboy Sam, Bottom Castiel, Boypussy, Cousin Lucifer, Creature Sam Winchester, Cunnilingus, Dogboy Sam Winchester, Dogboys & Doggirls, Dogboys have purely creature/animal minds, Extremely Dubious Consent, First Time, Good Lucifer (Supernatural), Heat Sex, Knotting, Mating Cycles/In Heat, Multi, Multiple Orgasms, Naive Castiel, Omega Castiel, Other, Owner Lucifer, Pet Sam Winchester, Rough Sex, Size Kink, Stud Sam Winchester, Taboo, Teen Castiel, Top Sam Winchester, Underage - Freeform, first knotting, human/dogboy, society considered bestiality
Language: English
Status: Completed
Published: 2018-09-10
Updated: 2018-09-10
Packaged: 2019-07-10 19:01:31
Rating: Not Rated
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 1,965
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/15955541
Author URL: https://archiveofourown.org/users/thewinchesterlifestyle/pseuds/thewinchesterlifestyle
Summary: Castiel whimpered, twisting in the guest room bed sheets, as a horrible heat burned inside of him.





	Mounted

**Author's Note:**

> Written for a prompt.

Castiel whimpered, twisting in the guest room bed sheets, as a horrible heat burned inside of him. Nothing he did helped to ease it. His boxers were long gone, the heavy comforter on the floor and the sheets were tangled around his legs but nothing helped. Not even the breeze coming in from the open window.

Something twisted painfully in his gut and he throbbed between his legs as his cunt clenched repeatedly.

He twisted again, panting and whimpering in pain, as the sound of the door creaking open barely registered. It was probably his cousin’s cat. He shifted himself up on his knees, shoved his face into the soft pillow, before reaching under to rub against his swollen clit and hope that helped.

It was terrible but as he sobbed into the pillow Castiel kept trying to get some kind of relief.

The mattress dipped with a heavy weight but Castiel was too focused on rubbing his clit and trying to get that horrible twisting feeling to ease to pay it much attention. It wasn’t until _something_ climbed on top of him, wrapped arms around his waist, and started moving against him that he realized anything was off. Something soft and warm brushed against his sweat damp skin. He couldn't bite back the whines spilling from his trembling lips.

Castiel tried to move away when something hard and thick rutted up against his cunt but the strong arms locked around him tightened and a vicious sounding growl had him freezing. He moaned as he pulled his head up and looked back to see his cousin’s dogboy mounting him.

It explained why instead of feeling skin against him Castiel had felt something softer.

The dogboy’s fur.

Embarrassed horror flashed through him. There were Alphas who strapped Omegas down and let dogboys, even catboys, mount and fuck them but it was considered a taboo to speak about in polite company. It was considered the equivalent of fucking an animal since dogboys and catboys were animal-minded. They didn’t think or act or reason like a human could. Everything was always pure instinct and lacked rational, informed thought.

He tried to move away again but the hold was strong and his cousin’s dogboy fucked roughly up against him despite Castiel’s attempts to free himself.

“Bad dog, Sam. Sam!"

The dogboy didn’t seem to hear him or if he did the dogboy didn’t care. He rutted roughly up against Castiel until his hard cock caught on Castiel’s slick soaked cunt and then Sam was _slamming_ inside with an excited grunt.

Immediately the dogboy started rapidly fucking him hard and fast. There was nothing Castiel could do once the dogboy had managed to sheath himself inside of his throbbing, aching cunt as the hold on him tightened viciously and the pace only seemed to increase the longer Sam fucked him.

It was nothing short of animalistic.

But it felt good because Castiel’s clenching cunt had felt empty.

Castiel sobbed for a different reason as his cunt eagerly and hungrily tightened repeatedly around the wide, long cock pumping through his slick soaked channel. Pleasure lit up inside of him with each thrust of the dogboy’s hips. He moaned loudly, whining and begging wordlessly for more. "Ohhhh. Oh oh oh please please."

Heavy balls slapped wildly against him as his cunt rhythmically clenched around the dogboy as he was fucked roughly. It was almost without thought that Castiel found himself shoving his hips back to meet each hard, deep thrust as the heat inside of him burned and burned. He was a mess. Whimpering and whining deep in his throat, cunt soaked and squeezing the cock fucking it, as a wet and lewd sound of the dogboy plowing through his wet channel filled the air. He shoved his hips back with increasing desperation.

A subconscious kind of instinct trying to encourage him to seek a breeding partner and encourage the one buried inside of him to breed his empty womb.

It wasn’t long before the dogboy’s knot started to catch on his cunt, tugging and popping free, only to cause Castiel to freeze in realization of what he was doing. For a moment he’d forgotten himself, forgotten _what_ was on top of him, as his instincts had dragged him into the kind of mindlessness Castiel had only ever heard about in health class and had managed to avoid with the medication his parents had purchased for him.

He tried to pull away but Sam snarled and fucked him harder, rutting viciously up against his cunt, until the dogboy was working his knot inside.

It swelled up, a hard and thick ball that pressed against Castiel’s tender inner walls, to tie them together for Castiel’s first knot. This time when Castiel tried to shy away, even as his cunt greedily and hungrily milked the knot nestled inside of his passage, it burned for a different reason as the knot tugged against his swollen entrance.

The dogboy shifted and Castiel cried out as pleasure shot through him. He could feel the way his cunt clenched violently as slick flooded his passage and soaked the dogboy’s cock even as Sam’s release coated his inner walls.

Sam collapsed on top of him, panting and spent, as his hips kept twitching forward and huffs of pleasure brushed against Castiel’s unmarked bonding gland.

With the awful heat inside of him temporarily banked Castiel was horrified, completely horrified, at the knowledge that a dogboy was knotted balls deep in his cunt and filling his womb with its seed.

He glanced over to see the door open but no one was standing there and Castiel was so grateful his cousin’s room was on the other side of the house on the second floor. Castiel flushed darkly in mortification. He had been _moaning_ and shoving himself back into the dogboy’s thrusts like a bitch in heat.

The weight on top of him was nothing more than an animal and he had let that animal mount him.

Lucifer’s words flashed through his mind.

_Make sure you shut the bedroom door at night. Sam hasn’t been fixed yet and he’s known for mounting Omegas. The breeder I bought him from used him to stud and to fuck Omegas for porn videos. You’ll only have to be careful this visit. He has an appointment for next Friday to have his balls removed so that should calm him down._

He clearly should have listened. Castiel could feel Sam testing his knot occasionally and settling back down when it remained firmly locked inside of Castiel’s cunt, pumping Castiel full of dogboy come, as his body milked every drop.

Castiel whimpered in humiliation. He could already feel the way his body was starting to heat up again. This wasn’t supposed to happen. The pills his parents had purchased were supposed to stave off his heats because they thought him too young for breeding and his parents wanted to choose an Alpha for him without worrying about explaining away an unwanted breeding.

He couldn’t tell anyone. Castiel swallowed and wished Sam’s knot would slip free so he could scrub himself clean.

Unfortunately it was a very, very long knot.

Castiel was half asleep when Sam shifted his hips and his knot popped free. Slick and come gushed out of Castiel’s fucked open cunt, trailing down and soaking him between his legs, as he clenched trying to limit the mess.

Seconds later Sam shoved his face up against him and enthusiastically lapped at the mess, rough tongue dragging over Castiel’s sensitive cunt and clit, as he cried out and slick gushed out of him in response to the arousal burning inside of him. His face flushed, his eyes hooded and hitching pants escaped his trembling lips at each pass of Sam’s tongue.

It felt so good.

It felt mind-numbingly amazing and Castiel’s fingers knotted in the sheets as more slick gushed out of him. He could feel the way Sam’s whole body shook with excitement, the dogboy’s tail wagging wildly, as he hungrily lapped at Castiel’s cunt.

Castiel was half out of it with need and pleasure when Sam mounted him again, chocolate fur brushing against his sweat damp skin, before the large breed dogboy was fucking up against his cunt once more with that thick, long cock seeking out his entrance.

It only took a few thrusts before Sam was once more buried balls deep in him and Castiel was being fucked by a dogboy for the second time in a short period of time.

Sam fucked like it was his very purpose, like it was his sole reason for existing, as Castiel could only moan and whine and sob at the sensation. He hated himself, hated how letting the dogboy brutally fuck him gave even the smallest amount of relief, but whenever he would come to his senses and try to move Sam would grip him tighter near his hips, fuck into him harder and snarl lowly.

Castiel found himself mounted, fucked and knotted six times throughout the night.

Morning saw Castiel’s cunt gaping, sloppy and well fucked as Lucifer’s dogboy mounted him for the seventh time with the morning light shining in through the window. Castiel was exhausted and had stopped struggling to get away from Sam after the second knot had gone down.

The only thing he had the energy to do was whimper as he remained there in the standard mounting position and the dogboy roughly fucked him again.

Sam’s thrusts were just as powerful, just as hard and single-minded as they were the first time Castiel had realized what had happened. He moaned brokenly into his pillow, the scent of fucking and Omega Heat thick in the air, as Sam moved faster and faster, rutting up against his cunt, until he finally fucked his knot into Castiel’s cunt.

Castiel came with a rough, soft cry as his cunt milked Sam’s knot and the dogboy draped over him. Sweat damp fur stuck to Castiel’s back, his ass and his thighs where Sam was positioned.

It was impossible to miss how content and pleased the dogboy was at having spent the night _breeding_ a whining Omega. Castiel listened to him panting, ignored the feeling of drool on his bare skin, as he waited out the most recent knot. He wanted to sleep, he wanted to shower and he wanted to spend the rest of his heat knotted.

Outside of the guest bedroom he could hear movement in the house and so could Sam. The dogboy perked up, body shaking with excitement, as he tugged on his knot and Castiel cried out in pain. His body locked down, clamping viciously on Sam’s knot, as the dogboy huffed in frustration and tried to tug his knot out again.

It was a torturous knot.

Finally, _finally_ , it popped free and Sam was off him. The dogboy shifted, bent and lapped at his cock before bounding out of the room, tail wagging with excitement, without a single glance back to the fucked out Omega lying face down on the bed.

Castiel squirmed at the wet, used feeling and how his cunt still throbbed with the need his Heat was sending racing through his tired body. He was sloppy, wet and sticky from seven knots. Somehow he managed to stumble up, the mess leaking out of his cunt and running down his thighs, before he moved towards the open door. The door was pushed closed, though Castiel missed how it didn't click, before he headed to the bathroom.

It would be an hour before he left the tub, Lucifer long gone to work, before Castiel would make it back to the bed and pass out on the ruined sheets only to wake up to Sam fucking his cunt once more.

**Author's Note:**

> Figured you all might miss fics with dogboys in them and this one is far lighter than the last several prompts I've posted fills for. I'm going to hope this one was a good choice to post next. I don't think I've ever posted a dogboy!Sam fic and who doesn't want a large breed dogboy!Sam to mount and fuck a whimpering, naive Omega Cas?
> 
> Note: Since readers seem to think there is something sinister or otherwise happening in this fic...Lucifer has NOTHING to do with what happened. He warned Castiel specifically to keep him safe. Castiel is the one who leaves his door open and who forgets to take his medication. Lucifer has nothing to do with it. It's all Castiel's own fault.  
>  
> 
> Please remember to leave a comment and let me know what you thought. Remember comments are motivation for continuing to write and post fanfics!
> 
>  
> 
> If you have a bottom!Cas prompt you can send it [here](https://surveynuts.com/surveys/take?id=176805&c=5013482597THNN). I'm looking for a few fresh prompts.


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